Kelp

Kelp, a member of the brown algae (Laminariales) family, thrives in the cold waters of the major oceans. This large species of seaweed is an excellent source of iodine, an essential element for healthy thyroid function in humans.
In Asia, especially Japan, seaweed has been an integral part of the daily diet for centuries. A well-known kelp species is kombu (Laminaria japonica), which is often cooked with rice for sushi. In addition to being one of the largest plants in the world, kelp is known for growing extremely quickly, sometimes up to three meters per day.